Risk factors for coronary heart disease and acute-phase proteins - A population-based study

Aims Circulating levels of C-reactive protein and serum amyloid A protein i ncrease markedly, and albumin levels fall, during the acute-phase response to tissue injury, infection and inflammation. Some acute-phase proteins hav e been associated with increased risks of coronary heart disease in long-te rm prospective studies. The aim of the present study was to determine wheth er circulating concentrations of C-reactive protein, albumin and serum amyl oid A protein are correlated with one another, standard vascular risk facto rs, markers of persistent infection, or indicators of socio-economic status . Methods and Results We report a cross-sectional study of 704 individuals wi thout a history of coronary heart disease from five general practices in Be dfordshire, U.K. Plasma levels of C-reactive protein and serum amyloid A pr otein were strongly associated with each other (2P<0.00001) and inversely r elated to levels of serum albumin (2P<0.00001). There were highly significa nt associations of plasma C-reactive protein concentrations with cigarette smoking and obesity (2P<0.00001 for each). Serum albumin levels were strong ly associated with blood pressure (2P<0.0001) and plasma lipids (2P<0.001), and concentrations of serum amyloid A protein were strongly correlated wit h obesity (2P<0.0001). Conclusion previously reported long-term prospective studies have found an increased risk of coronary heart disease of about 50% in people with raised baseline levels of plasma C-reactive protein or low albumin. The strong cr oss-sectional associations we have found between levels of these proteins w ith each other and with concentrations of serum amyloid A protein suggest t hat some underlying process related to inflammation is likely to be of rele vance to the causation of disease. Further studies are needed to determine if the strong associations of plasma levels of C-reactive protein with ciga rette smoking and obesity indicate that this particular protein can mediate some of the effects of those risk factors on coronary heart disease.